Democrats inch closer to nominee

After the longest primary season in years, Senators Barack Obama and Hillary Clinton face off in their final contest before Democrats choose their nominee to face John McCain in America's presidential election in November. The South Dakota and Montana pri

Obama looks poised to claim the presidential nomination; he's expected to win the majority share of the 31 delegates on offer.

He still needs the support of about 30 undecided super delegates to claim victory.

It could mean the end of the presidential road for Senator Clinton, despite a convincing win in the Puerto Rican primary on Monday.